Termination for a line card in a telecommunication system

ABSTRACT

A system of terminating signals in a telecommunication system is disclosed. In one embodiment a line card comprises functional circuitry, line card connector contacts and a termination resistor. The functional circuitry is used to interface first type ports with second type ports. The line card connector contacts are adapted to be selectively coupled to a backplane of a chassis. The termination resistor is adapted to terminate signal lines when a jumper is coupled across select line card contacts.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 10/351,016 filed on Jan. 24, 2003 and entitled “TERMINATION FORA LLINE CARD IN A TELECOMMUNICATION SYSTEM” (the '016 Application). The'016 Application is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to telecommunication systems andin particular the present invention relates to a termination resistorsystem for a line card in a telecommunication system.

BACKGROUND

Digital subscriber line (DSL) and T1/E1 chassis are used intelecommunication systems. One function of a DSL chassis is to interfaceports and a function of a T1/E1 chassis is to interface T1/E1 ports. Thesame chassis can support either DSL or T1/E1 ports depending upon linecards used. The chassis includes a backplane. The backplane is adaptedto deliver power to and provide high speed interconnections between,line cards, multiplexer cards and a management card. The line cards,multiplexer cards and management card are all adapted to plug into thebackplane of the chassis. Line cards (or modules) are printed circuitboards that provide operational functions for designated phone lines ortelephones in a telephone system.

The receive input of a DSX-1 line needs to be coupled across atermination resistor of a select value. One typical method of achievingthis is by placing the termination resistor on the backplane. However,this limits the ability of using the same slot in the backplane forother purposes that don't require the use of a termination resistor. Forexample, in a situation where DSL ports are designed to not requiretermination for any loop. This would create a contradiction of having atermination for the DSX-1 ports but not for the DSL ports in the samechassis. Accordingly, it is desired in the art to have a chassis andline card combination that does not require a termination resistor onthe backplane. Moreover, it is desired in the art to have a line cardthat is designed to work in both a chassis that has a backplane with atermination resistor and a chassis having a backplane without atermination resistor.

For the reasons stated above and for other reasons stated below whichwill become apparent to those skilled in the art upon reading andunderstanding the present specification, there is a need in the art foran improved line card and chassis system.

SUMMARY

The above-mentioned problems of line card termination in atelecommunication system and other problems are resolved by the presentinvention and will be understood by reading and studying the followingspecification.

In one embodiment, a line card for a telecommunication system isdisclosed. The line card comprises functional circuitry, line cardconnector contacts and a termination resistor. The functional circuitryis used to interface first type ports with second type ports. The linecard connector contacts are adapted to be selectively coupled to abackplane of a chassis. The termination resistor is adapted to terminatesignal lines when a jumper is coupled across select line card contacts.

In another embodiment, a telecommunication system is disclosed. Thetelecommunication system comprises a chassis and one or more line cards.The chassis has a backplane. The backplane has a plurality of backplaneconnectors electrically coupled to the backplane. Each of the one ormore line cards have a plurality of electrical card connection contactsthat are adapted to be selectively coupled to an associated backplaneconnector. At least one of the one or more line cards further comprisesfunctional circuitry to interface DSX-1 or DSL ports with other portsand a line card termination resistor. The line card termination resistoris adapted to terminate DSX-1 lines when a jumper is coupled acrossselect electrical line card connector contacts.

In another embodiment, a line card for a telecommunication system isdisclosed. In this embodiment the line card comprises functionalcircuitry, line card connector contacts and an impedance network. Thefunctional circuitry is used to interface first type ports with secondtype ports. The line card connector contacts are adapted to beselectively coupled to a backplane of a chassis. The impedance networkis adapted to terminate signal lines when a jumper is coupled acrossselect line card contacts.

In further another embodiment, a method of terminating signal lines isdisclosed. The method comprises coupling signal lines to a chassis. Whena backplane of the chassis includes a backplane termination resistor,terminating signals with the backplane termination resistor. Moreover,when the backplane of the chassis does not include a backplanetermination resistor; terminating the signals with a line cardtermination resistor contained on a line card.

In still yet another embodiment, a method of interfacing DSX-1 or DSLsignals, the method comprising coupling the DSX-1 lines to a backplaneof a chassis. Coupling the DSL lines to the backplane of the chassis.When a backplane includes a backplane termination resistor, terminatingDSX-1 signals with the back plane termination resistor. When thebackplane of the chassis does not include a backplane terminationresistor; terminating the DSX-1 signals with a line card terminationresistor contained in a line card. Interfacing the DSL and DSX-1 signalswith the line card.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more easily understood and furtheradvantages and uses thereof more readily apparent, when considered inview of the description of the preferred embodiments and the followingfigures in which:

FIG. 1 is a schematic diagram of a line card of one embodiment of thepresent invention;

FIG. 2 is a front perspective view of a chassis and line cards of oneembodiment of the present invention;

FIG. 3 is a front perspective view of a backplane connector of a chassisof one embodiment of the present invention;

FIG. 4 is a front perspective view of another embodiment of the linecards and chassis of the present invention; and

FIG. 5 is a schematic diagram of another embodiment of the presentinvention.

In accordance with common practice, the various described features arenot drawn to scale but are drawn to emphasize specific features relevantto the present invention. Reference characters denote like elementsthroughout Figures and text.

DETAILED DESCRIPTION

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings, which form a parthereof, and in which is shown by way of illustration specific preferredembodiments in which the inventions may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention, and it is to be understood that otherembodiments may be utilized and that logical, mechanical and electricalchanges may be made without departing from the spirit and scope of thepresent invention. The following detailed description is, therefore, notto be taken in a limiting sense, and the scope of the present inventionis defined only by the claims and equivalents thereof.

Embodiments of the present invention include a line card that is adaptedto work in any chassis that has a termination resistor built into thebackplane of the chassis as well as a chassis without terminationresistor built into the backplane. Referring to FIG. 1, one embodimentof a line card (module) 100 of the present invention is illustrated. Asillustrated, line card 100 includes functional circuitry 104 and atermination resistor 102. The functional circuitry 104 performs thefunctions of the line card 100 such as interfacing the DSX-1 or DSLports with other ports (first type ports with second type ports). Theline card termination resistor 102 for a DSX-1 line card is included incircuit 107. As illustrated in the embodiment, DSX-1 lines are connectedthrough card connection contacts C8 and C9 to circuit 107. The cardconnection contacts are generally designated by 106. It will beunderstood in the art that the line card will generally have many morecard connection contacts 106 than what is shown in FIG. 1 and that onlya limited number of card connection contacts 106 are shown to betterillustrate the features of the present invention.

A front perspective view of one embodiment of a telecommunication systemchassis 200 is illustrated in FIG. 2. Also illustrated are line cards100, multiplexer cards 103 and management card 101. Further shown isbackplane 202 and backplane connectors 204. The line cards 100,multiplexer cards 103 and the management card 101 are all adapted to beinserted in associated backplane connectors 204 to create electricalconnections to the backplane 202. A typical method of creating anelectrical connection between the cards and the backplane 202 is byusing a DIN connector or similar method.

In one embodiment, backplane 202 of chassis 200 does not include atermination resistor to terminate DSX-1 lines. As described above, theline cards 100 of FIG. 1 include line card termination resistor 102adapted to terminate the DSX-1 lines. Referring to FIG. 3, an example ofone embodiment of a backplane connector 204 is illustrated. In thisembodiment, the backplane connector 204 contains a jumper 300 that iscoupled across electrical backplane connector contacts 302 and 304.Backplane contacts 302 and 304 are adapted to be in electricalconnection with contacts B11 and C10 of line card 100 respectively whenline card 100 is inserted into the respective backplane connector 204.As illustrated, jumper 300 completes circuit 107 that contains thetermination resistor 102 to terminate the DSX-1 line. Although jumper300 is illustrated as being in the backplane connector 204 in thisembodiment, it will be understood in the art that the jumper could belocated in other locations as well, such as the backplane, and that thepresent invention is not limited to having jumper 300 in backplaneconnector 204.

FIG. 4 illustrates the use of line card 100 in a chassis 500 that has abackplane termination resistor 502 coupled to the backplane 506. Asillustrated in the embodiment of FIG. 4, line cards 100, multiplexercards 503 and management card 501 are adapted to be inserted intorespective backplane connectors 504. In this embodiment, when a linecard 100 is inserted in the backplane connector 504 no jumper is presentto provide an electrical connection across pins B11 and C10 of line card100. As a result, circuit 107 that includes line card terminationresistor 102 in line card 100 remains open. Therefore, a backplaneresistor such as backplane termination resistor 502 is used instead ofthe line card termination resistor 102 to terminate DXS-1 lines in theembodiment of FIG. 4. Accordingly, line card 100 is adapted to be usedin a chassis that provides a termination resistor in the backplane and achassis without a termination resistor in the backplane.

Referring to FIG. 5, another embodiment of a line card 600 of thepresent invention is illustrated. Line card 600 is adapted to apply to achassis that uses an impedance to terminate line signals. As illustrate,FIG. 5 includes functional circuit 604, circuit 607 and line connectorcontacts 660. Circuit 607 includes impedance network 602 coupled in asimilar fashion as the termination resistor of FIG. 1. The impedancenetwork 602 is adapted to terminate the line signals. The line connectorcontacts 660 include card collector contacts 616 and 614. Card collectorcontacts 616 and 614 are adapted to be electrically coupled to a jumpersimilar to jumper 300 of FIG. 3. As in the above described embodiments,the jumper is used when a backplane does not contain an impedance neededto terminate the line signals. Card collector contacts 660 also includecard collector contacts 608 and 610 which are adapted to couple signallines to the line card, similar to card collector contacts C8 and C9. Infact, in one embodiment, card collector contacts 608 and 610 are pins C8and C9 and card collector contacts 616 and 614 are pins B11 and C10.Further, in one embodiment the line signals are DSX-1 signals coupled toDSX-1 lines. In yet another embodiment the impedance network includes aresistor similar to termination resistor 102 of FIG. 1. In addition, itwill be understood in the art that the embodiments of the presentinvention can be applied to any type of line card and that the presentapplication is not limited to DSX-1 and DSL flavors.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement, which is calculated to achieve the same purpose,may be substituted for the specific embodiment shown. This applicationis intended to cover any adaptations or variations of the presentinvention. Therefore, it is manifestly intended that this invention belimited only by the claims and the equivalents thereof.

1. A telecommunication chassis comprising: a backplane; and a pluralityof backplane connectors, each backplane connector coupled to thebackplane, each backplane connector is further configured to couple aline card to the backplane, each backplane connector having backplanecontacts to provide electrical connections to a coupled line card; andat least one jumper, each jumper coupled to provide an electricalconnection between a pair of backplane contacts of an associatedbackplane connector, wherein when a line card having a terminationresistor is coupled to the at least one backplane connector that has thepair of backplane connectors that are in electrical connection, thetermination resistor of the line card is coupled for use by the jumper.2. The telecommunication chassis of claim 1, wherein the at least onejumper is located in its associated backplane connector.
 3. Thetelecommunication chassis of claim 1, wherein the at least one jumper islocated in the backplane.
 4. A line card for a telecommunication system,the line card comprising: functional circuitry of the line card; linecard connector contacts configured to be selectively coupled tobackplane contacts in an associated backplane connector of atelecommunication chassis, the line card connectors including a firstline card connector and a second line card connector; a first signalpath; a second signal path, the second signal path coupled to the firstline card connector; and a termination resistor having a first sidecoupled to the second line card connector and a second side coupled tothe first signal path, wherein an electrical connection between thefirst line card connector and the second line card connector terminatesthe first and second signal paths across the termination resistor. 5.The line card of claim 4, wherein the functional circuitry includescircuitry to interface first type ports with second type ports.
 6. Theline card of claim 4, wherein the first and second signal paths areDSX-1 signal paths.
 7. A line card for a telecommunication system, theline card comprising: functional circuitry of the line card; line cardconnector contacts configured to be selectively coupled to backplanecontacts in an associated backplane connector of a telecommunicationchassis, the line card connectors including a first line card connectorand a second line card connector; a first signal path; a second signalpath, the second signal path coupled to the first line card connector;and an impedance network having a first side coupled to the second linecard connector and a second side coupled to the first signal path,wherein an electrical connection between the first line card connectorand the second line card connector terminates the first and secondsignal paths across the impedance network.
 8. The line card of claim 7,wherein the functional circuitry includes circuitry to interface firsttype ports with second type ports.
 9. The line card of claim 7, whereinthe first and second signal paths are DSX-1 signal paths.